Alkylation of hydrocarbons



June 18 1946. L.A. CLARKEV ALKYLATION oF HYDRocARBoNs Filed Dec. 27. 1943 June 18, 1946. l.. A. CLARKE ALKYLATION OE HYDROCARBONS Filed Dec.'27, 1943 2 Shears-Sheet 2 INVENTOR l Patented June' 18, 1946 A `V UNITED ALxrLA'rIoN or mnocAaBoNs Louis A. Clarke. Fishkill. N. Y., assigner to The Texas Company, New York. N. Y., a corporation of Delaware Application December 27, 1943, Serial No. 515,649 s claims. (ci. asotassi This invention relates to the alkylation of olefin hydrocarbons with parafiin hydrocarbons in the presence of an alkylatlon catalyst comprising a metallic halide such as aluminum chloride. It has particular application to the manufacture of high anti-knock gasoline hydrocarbons suitable for use in the production of motor fuel. 4

This is a continuationhin-part of my copending application serial No. 327,575, filed April 3,1940, and of my copending application Serial No. 439,299, filed April 17, 1942.

Broadly, the invention contemplates a process for the alkylation of olefin and paraiiin hydrocarbons by contact with an alkylation catalyst comprising an active metallic halide. dispersed or suspended in an agitated liquid medium. The liquid medium comprises complex metallic halide-hydrocarbon compounds such as produced in a conventional alkyla-tion reaction wherein a catalyst such as aluminum chloride has been employed with the resultant production of complex compounds.. The complex material may be such as produced in the isomerization of normal parain hydrocarbons during contact with anhydrous metallic halides. A suitable complex material may also be prepared directly by reacting aluminum chloride or otheractive metallic halide with paraiiin or olefin hydrocarbons, for example kerosene or naphtha. It may also be prepared by reacting the metallic halide with alkyly halides such as propyl and butyl chlorides.

In accordance with the invention, a large liquid body of preformed metallic halide-hydrocarbon complex is maintained in an agitated condition within the reaction zone. The active metallic halide catalyst is suspended or dispersed in the agitated liquid and the reaction is effected in a contijiuous manner by continuously passingthe n oleun and paraiiin hydrocarbons to be treated through the agitated mass.

The process of this invention is particularly applicable to the alkylation of ethylene or hydrocarbon mixtures containing mainly ethylene as the olei'lnic constituent with an isoparailin hydrocarbon such as isobutane for the production of low boiling normally liquid 'gasoline hydrocarbons of high anti-knock value.

' Alkylation of olefin and isoparafiln hydrocarbons with aluminum chloride as a catalyst has been proposed previously. For example, U. S.

,Patent adressa describes the aikyicticn of ctn-- me with isobutane by contact with solid aluminum chloride in a batch type of operation at relatively low temperatures.

Heretofore, considerable ditllcuity has been experienced in attempting to alkylate hydrocarbons with aluminum chloride as the catalyst in a continuous manner due to the rapid deterioration of the catalyst. During the reaction, the metallic halide enters into reaction with theA hydrocarbons or hydrocarbon products forming gummy and sticky compounds.

This gummy material soon results in binding the solid particles of catalyst together producing an impervious mass which ultimately exerts little or no catalytic eiect. In this way emcient contact .between the active halide and the hydrocarbons undergoing the treatment is prevented.

The present invention involves the discovery that the process can be carried out continuously without encountering the foregoing difliculties by maintaining the active metallic halide suspended or dispersed in an agitated liquid body of preformed metallic halide-hydrocarbon complex compounds so that emcient contact between the hydrocarbons and the active catalyst is realized over a prolonged period of time. To some extent the active metallic halide may bey dissolved in the complex liquid. At any rate it has been found that by maintaining the proportion of complex liquid to active metallic halide relatively large it is possible to maintain the metallic halide in an active and effective form overa prolonged period of operation.

In order to describe the invention further, reference will now be made to the accompanying drawings which illustrate preferred embodiments for carrying out the process in a continuous manner.

Fig. 1 is a diagrammatic view of apparatus, including an agitated reactor of the jet type with catalyst recycle, for carrying out the method of the present invention; and

Fig. 2 is a diagrammatic view of apparatus, including a reactor of the rotary or centrifugal pump type, together with fractionating and isomerizing equipment. particularly designed for handling refinery cracking gas fractions in isobutaneethylene alkylation.

Referring to Fig. 1 of the drawings, the hydrocarbon feed comprising olefin and isoparaiiin hydrocarbons is drawn from a source not shown -through a. pipe l communicating with a pipe 2 and 65 The reaction mixture is continuously drawn encara@ oi from the top oi vthe vessel through a pipe d leading to a settler ii. Any gaseaus constituents accumulating in the upper portion of the reaction vessel may be vented ofi` through a valved pipe t.

The mixture entering the settler 5 from the reaction vessel comprises allrylated hydrocarbons and metallic halide-hydrocarbon complex liquid as well as solid particles of the metallic halide suspended therein. This mixture undergoes phase separation in the settler 5, the compiex liquid containing solid metallic halide settling to the bottom oi the settler. The separated complex liquid and suspended matter is continuously drawn E through a pipe i and all or in part returned by a pump 8 to the bottom ci the reaction vessel il, that portion not returned being discharged from the system through a pipe 9.

The recycling rate is maintained sumciently high so as to thoroughly agitate the mixture within the reaction vessel 3 and thereby keep the solid catalyst particles suspended in the liquid mixture.

A hopper device i0 is provided through which to introduce fresh metallic halide in Ipulverulent form to the upper portion of the reaction vessel. The fresh catalyst is introduced continuously or intermittently so as to provide make-up -sudcient to compensate for catalyst being discharged from the system in the form of complex material. The make-up is added in suicient amount to insure the presence of a substantial amount of active catalyst suspended and dissolved in the agitated liquid mixture.

The upper phase separated in the settler comprising alkylated hydrocarbons is drawn o through a pipe ii to a fractionator or stabilizer i2 wherein normally gaseous hydrocarbons including propane and isobutane may be removed in vapor form through a pipe i3 leading to an auxiliary iractionator. ld. In the fractionator id propane and other light gaseous hydrocarbons may be separated and discharged through a pipe i5 while a condensed fraction comprising isobutane is withdrawn throughs, pipe i8. The isobutane fraction so removed may be returned all or in part to the reaction vessel as indicated.

Provision is made' for venting gaseous constituents from the settler E through a vaived pipe I'i. Such bases may include methane, ethane, hydrogen and some hydrogen chloride. The gases so removed may be subjected to furthe* -processing for the purpose of separating hydrogen chloride and isobutaneand returing them to the reactor 3, the separated hydrogen chloride being used to activate the metallic halide catalyst and the isobutane for reaction with fresh olen feed.

v The condensate withdrawn from the bottom of the fractionator i2 through a pipe I8 will comprise gasoline hydrocarbons produced in the reaction and suitable for the production of high anti-knock motor fuel.

When alkylating ethylene or an olefin fraction consisting essentially of ethylene with is'obutane, the reactionvessel is advantageously maintained at a temperature of at least around 110 F. or at a temperature in the range of 11G-130 F. and under a, pressure of around cess or isoparain to olefin, for example about d one molal part of olen to rive parts of isoparamn.

When operating in accordance with the method -of ow illustrated for the .alkylation of ethylene and in which fresh aluminum chloride is being added continuously, it is desirable to add continuously a small amount of .propylene or butylene so as to maintain during the alkylation reaction a complex mixture of desired charac ter, namely, a more satisfactory fluid medium in which to suspend the solid aluminum chioride. The amount of propylene or butylene so added should be'substantially less than 20% by weight of the ethylene being charged and preierably is in the range of about 5 to 10%.

The procedure may be modified so that the aluminum chloride may be added continuously in the form lof a suspension or dispersion in preformed aluminum chloride-hydrocarbon complex.

In any event, it is deemed desirable to have a small amount of hydrogen chloride present in the catalyst.

While the process of the present invention employing the fortified aluminum chloride-hydrocarbon complex catalyst can be used for the alkylation of various isoparafiins, such as isobutane and isopentane, with various olenns including propylene, butylenes, pentalenes, olefin polymers, cracked naphtha fractions, etc., it is particularly advantageous for the aikylation oi isobutane with ethylene for the production of 2,3 dimethyl butane or an alkylate of high antiknock value containing a high proportion of 2,3 dimethylbutane.

I have found that by the use oi diierent and critical conditions of operation in this isobutaneethylene alkylation, a substantially increased yield of a markedly diierent and superior type of alkylate consisting largely of the isohexane, 2,3-dimethyl butane,`1can be produced in con tinuous operation with greahy increased catalyst life. The process of the present invention can be employed to produce substantially pure 2,3 dimethyl butane in large yields, or can be utilized to 1produce alkylate containing the high content of 2,3-dimethyl butane and possessing superior qualities of boiling distribution range, higher octane and low volatility or R. V. P., which makes it an excellent blending stock for motor fuel or aviation gasoline.

In accordance with the 'present invention, isobutane is alkylated with ethylene in a continuous process wherein a much larger volume ratio of the aluminum chloride-hydrocarbon complex catalyst to total hydrocarbons is maintained in the reaction zone than has heretofore been proposed. and wherein a much shorter time of contact between the reacting hydrocarbons and the catalyst than has heretofore been suggested, is employed. Thus, a volume ratio of catalyst to total hydrocarbons in the reaction zone of at least 0.221, and preferably of the order of about 0.5:1 to lzl or higher, is used. The time of contact is reduced to less than twenty minutes, and may be as Y tice in this art, where. substantial amounts oi a carbons treated have vbeen specified. only very.

small amounts of HCl promoter less than about 0.2% by weight of the hydrocarbon charge in continuous operation are utilized. Preferably, the

Y proportion oi HCl on the -basis of the hydrocarbon charge varies from abouta trace to about 0.1% by weight. The hydrocarbon charge stocks may contain suiilcient water to produce this ...small amount of HC1 by reaction with the aluminum chloride; or small amounts of HCl,"'water, alkyl chloride or other material producing the minute amount of HCl promoter inthe reaction zone can be added continuously or intermittently, such as with the hydrocarbon charge or with the recycled catalyst.' Higher proportions of promoter have been found to cause degradation of the product and involve other disadvantages.

The hydrocarbon charge may comprise substantially only ethylene as the olenic constituent thereof, but a small amount of propylene within the critical range set forth above is preferably included in the charge to maintain the fluidity of the complex catalyst in continuous operation. Higher proportions of propylene result in substantial alteration of the composition'oi the product with a resultant lowering in octane number thereof `and a reduction in catalyst life.

v The charge may comprise substantially pure hydrocarbons, namely, isobutane and ethylene, or ethylene containing a small proportion of propylene; but preferably reilnery fractions are utilized to avoid the expense inherent in effecting separation of the pureA compounds.

For example, a C: and lighter fraction contain- 6 about 8085%, of 2,3-dimethyl butane. The remaining content of the alkylate is made up largely ing ethylene, ethane, hydrogen and methane and with a small proportion of propylene as specified, can -be satisfactorily employed under the conditions stated. The isobutane may be obtained from any suitable source, such as from reilnery gas or from natural gas, and may be mixed with a small proportion of normal butane without deler.,

and higher with respect to the olefin or ethylene y conditions. the gaseous Ca fraction is intimately mixed with the relatively large liquid body of aluminum chloride-hydrocarbon complex catalyst and liqueed isobutane such that the ethyleneis rapidly absorbed and reacted with the isobutane to produce the desired normally liquid alkylate. The reaction products pass continuously to a settling zone where a liquid hydrocarbon phase containing the excess isobutane and heavier separates from the catalyst'phase, which latter may be continuously recycled, in Whole or in part, with suitable fortication with fresh aluminum chloride as needed, to the reaction zone. The xed and unreacted gases of the C: and lighter fraction are released from the settling zone and thus separated from the liquid product which is then neutralized. stabilized and fractionated into the desired motor fuel fractions.

Under the conditions specified, a debutanized liquid alkylate is obtained which has a volume of octanes with only a few percent of pentanes and material higherboiling than octanes. Where propylene is present in the charge, a small proportion of heptanes are also produced. At least about -98% of the product boils below 311 F. and this fraction has a C. F. R. M. octane in excess of 90 and generally about 92-95.

. Referring to Fig. 2 of the drawings, a Cz and lighter cracked gas refinery fraction. containing a small amount not more than 10% by weight of propylene on the basis of the ethylene therein, is introduced by pipe 2|. A pump 23 forces the Cz and lighter fraction'into a continuous reactor 24 ofthe centrifugal pump type having large clearances between the impeller and rotor housing.

A stream of liqueed isobutane is introduced by line 25 so as to mix with the C2 and lighter fraction prior to contact of the latter with the complex suspension catalyst maintained in the reacproportion-of isobutane is regulated to provide the desired large molar excess on the basis of the olefin charged; as set forth above. A quantity of complex suspension catalyst is maintained within the circulating system, so that a volume ratio of catalyst to total hydrocarbons of the order previously stated is continuously maintained within the reaction zone.

Reaction products are' continuously discharged by line 21 into the lower portion of a vertical settler 28 equipped with a water Jacket 2'3, whereby the temperature of both the reaction and settling zones is maintained at about -130 F. or somewhat higher. In settler 28, stratification into a lower complex suspension catalyst layer, an upper liquid hydrocarbon layer, and a supernatant atmosphere of iixed and unreacted gases occurs. These gases comprising the unreacted ethane, methane and hydrogen are releasedfrom the upper portion of settler 28 by line 30 equipped with pressure release valve 3|. Catalyst is continuously returned by the large diameter line 32 to the inlet 33 of reactor 24.

In order to maintain the activity of the catalyst during long periods of .continuous operation, a portion of the circulating catalyst body is 'withdrawn by valve controlled line 35 connecting with valve controlled discharge line 38 and valve controlled line 31. The major portion oi' the withdrawn catalyst preferably passes by line 31 into a mixer 38 equipped with suitable feed hopper 39 through which makeup solid aluminum chloride is supplied to the contents within mixer 38. The revivied complex suspension is returned by pump d0 through line 4| to the reaction zone. A line d2 provides for the introduction of any required amount of HC1 into the recycled catalyst stream passing to the reactor.

The vunstabilized hydrocarbon liquid within set--l tier 28 is continuously removed by pump 43 con; trolled by a constant leveling device and passed through line 44 into a neutralizer 45 wherein it is treated and neutralized by caustic soda solution eous hydrocarbons may be removed from -thelupper portion of neutralizer 45 by line 48 containing a suitable pressure release valve.

The neutralized hydrocarbons pass by line l0 into the stabilizer Il wherein the alkylate is de#- any excess being discharged by line lili.

accesso butaniaed. The removed gases consisting essen.

tially of the excess isobutane together with a niinor proportion of normal butane are passed by line -52 to a butane fractionator d3 to be hereinafter further described.

The stabilized C2 alkylate passes from the lower portion of stabilizer bi through line 55 to fractlonator 5B where the alkylate is separated into theA desired motor fuel fractions. ject is to produce substantially pureZdimethyl butane, the fractionator may be operated to take overhead by line il@ and Css, and to remove by side stream d@ a close-cut hexane fraction having a boiling range of about 12S-150 F., the remain ing alkylate being discharged as bottoms by line 6@ for use in motor fuel manufacture or other suitable purpose. In this case, valve t2 is open and valve 63 is closed. The side stream passes into an accumulator 6d from which vaporized hydrocarbons maybe removed by overhead line S5 connecting with the gasdischarge line d@ through f which the gaseous products may be led to suitable condens/ers for recovery of the desirable pentane fraction. inasmuch as this fraction contains a high proportion of isopentane, it maybe led to a further fractionator where substantially pure isopentane may be recovered for blending stock.

If desired, fractionator 56 may be operated to take overhead a Cry-Cs fraction; and in this case valve t2 is closed and valve il@ is opened so that the fraction passes through condenser 6B into accumulator 6s, the side stream 59 being closed. Where the entire alkylate boiling within the aviation range is desired,v fractionator Eat may be operated to take overhead a 311 F. end point fraction which passes through condenser 66 into accumulator 6d, and only the small higherv boil' ing bottoms is removed by line 66 While a single fractionator 56 has been shown, it is of course obvious that one or. more fractionators 'may be employed in series, whereby any desired close-cut fraction such as substantially pure 2,3-dimethyl butane may be obtained.

A bottoms fraction consisting essentially of normal butano is removed by line @il from the butane fractionator S3 and any portion thereof passed to a conventional isomerization unit lil, In the isomerlzation unit illu, the normal butane is converted to the extent of about 50-60 or more -by volume into isobutane, such as by treatment in well known manner with conventional isomerization catalysts of the character of aluminum chloride, as disclosed in U. S. Patents Nos. 2,271,860, 2,208,362, 2,249,366 and 2,266,011. As the isomerization step per se forms no part of the present invention, further description thereof is thought unnecessary.

The resulting isomerized products are returned by line l02 to fractionator 53. Make-up isobutane for the system may be supplied .by a mixed n-bitane-isobutane stream, such as a C4 fraction from the stabilization of natural gasoline, which is int troduced by line into fractionator 53. Prefer ably, the points of introduction of lines 52. 98

. and |02 into fractionator 53 are at different levels, depending upon the isobutane content of the materials handled by these various lines. .The overhead gases from the stabilization of the C2 alkylate being highest in isobutane content are introduced adjacent the upper end of the butane dll fractionator. The isomerization products of line |02, being generally lower in isobutane content,

are introduced below the mid-portion of the frac'- tionator: and the Ci. fraction from the stabili sation. of the natural gasoline, which nerally runs in excess of 60% by volume of n-butane is introduced at a still lower point. With suitable reflux, as is well known, it is possible to take overhead by line ifld an isobutane-rich fraction consisting of about or more of isobutane by volume. This fraction is compressed and liqueed by compressor it and cooler lili?, and recycled by line i'l to line 26 and the allrylatiofn reactor. Any additionalisobutane required for the process may be introduced from an extran neous source by line Idil.

An important feature of the present invention is based on the discovery that an aluminum hal ide-hydrocarbon complex alone, that is, the clear complex liquid separated from unreacted hydrocarbon andany non-liquid sludge, is comparatively inactive for this alkylation reaction, or has at best merely a flash activity which is rapidly spent in continuous operation. When it is at tempted to maintain the activity of such a complex liquid in continuous operation by discharge of a portion of the liquid and fortification with fresh complex liquid, this requires an uneconomical amount of aluminum halide in preparing sumcient fresh make-up complex liquid, and the results are not satisfactory. In accordance with the present invention, the preformed complex liquid is activated for use in ,the alkylation operation by the addition of fresh aluminum halide so as to disperse the added aluminum halide in an active form in the liquid complex. Very satisfactory complex liquids are obtained by heating aluminum chloride with kerosene or other light oil petroleum fractions, such as a higher boiling naphtha ora gas oil. factory complex liquid 'is prepared by reacting aluminum chloride with tertiary butyl chloride. It is to be noted thatthe complex liquid is of the same general character as that formed from the active aluminum halide when the latter is consumed in the alkylation operation.

To the body of preformed aluminum halidehydrocarbon complex liquid is added additional aluminum halide to form the so-called activated complex catalyst. This consists of the complex liquid containing suspended and/or dissolved aluminum halide in active form. When utilizing this activated complex catalyst, it appears that mainly the active dispersed aluminum halide is consumed; and the activity of the catalyst in con-A tinuous operation is maintained'by adding additional fresh aluminum halide to the originally prepared activated complex catalyst, either continuously or intermittently. It has been found that by maintaining the proportion of complex liquid to added active dispersed aluminum halide relatively large, it is possible to maintain the catalyst in an active and effective form for along period of continuous operation by the addition of a relatively small amount of fresh aluminum halide, with resulting high economy in the consumption of aluminum halide. A large body of the activated complex catalyst relative to the totalhydrocarbons maintained at any one time in the reaction zone can thereby be economically used for best' results. This provides highly effective contact between the dispersed active aluminum halide and the reacting hydrocarbons. Further, by the use of a small proportion of higher molecular weight olefin, such as propylene, which should be present in an amount less than about 10% by weight of the ethylene in the charge, coupled with the addition of fresh aluminum halide Also, a very satis- 9' y to the catalyst body as the operation proceeds, and preferably with the addition of a small proportion of a hydrogen halide less than 0.1% by weight of the hydrocarbons in the reaction mixture, the catalyst can be maintained in `a iluid and pumpable condition over long periods ofoperation while its activity is preserved at a. high level.

In the preparation of the aluminum halide-hydrocarbon complex liquid, the proportions of the aluminum halide and the hydrocarbon or alkyl halide can be varied materially, since the aluminum halide reacts with the oil to form a complex liquid and unreacted oil can then be separated from the heavier complex liquid by stratification. As excess of the aluminum halide on the basis oi the oil may be used, and the complex liquid readily separated by decantation from the excess unreacted non-liquid or solid aluminum chloride sludge. Frequently in the preparation of the complex liquid, there will remain both unreacted hydrocarbon and non-liquid aluminum halide sludge which are separated from the complexliquid.

Any of the above complex liquids -themselves are comparatively ineffective as alkylation catalysts, particularly in the alkylation-of isobutane with ethylene where poor yields of products generally lower in 2,3 dimethylbutane content are` obtained. However, when a small proportion of fresh aluminum halide is added to and retained in active dispersed form in the complex liquid, a superior catalyst for purposes of the present invention is produced. The amount of active aluminum halide maintained dispersed in the complex liquid can vvary Within wide limits, it being suicient to merely add enough aluminum halide to substantially saturate the complex liquid with dissolved aluminum halide, provided the activity is then maintained in continuous operation by frequent or continuous addition of fresh aluminum halide to the vcatalyst body. On the other hand, a sufficient amount of aluminum halide may be initially added to the preformed complex liquid to more than saturate that liquid, the excess then remaining in suspended form in the catalyst body. The upperV limit is determined by the ability oi? the complex liquid to keep the excess suspended aluminum halide properly dispersed to avoid settling in and clogging f the circulating lines and tanlrs, and so that the catalyst has proper viscosity and fluidity to he readily pumped through the system. The latter type of catalyst retains its, activity over a substantially longer period of continuousoperation without tortlcation with additional fresh aiuminum halide, since there is a larger amount of active dispersed aluminum halide to be consumed before the activity of the activated cetalyst'is impaired; and, in this case, the fortification of the catalyst during continuous operation may be made intermittently at lessirequent intervals oi' time, although continuous fortication can also be used with good results. Generally, solid aluminum chloride in particle form is initially added V I ance with the present invention may be as low as one pound ot aluminum `chloride per 20-30 or more gallons of debutanized alkylate.

The present invention is markedly distinguished in operation and beneficial results from that previously proposed in Patent No, 2,174,883

sult thatl the solid catalyst settles out in 'quiescent parts of thesystem, and the lines may soon become clogged. Moreover, while the solid aluminum chloride Iparticles tend to react with the hydrocarbons, particularly the heavier alkylate, to form complex, this reaction is slow at the temperatures employed for catalytic alirvlatlon. The solid particles of aluminum chloride ilrst pass through a sticky gummy stage in which the particles tend to bind together into an impervious mass of little or no catalytic effect. In a continuous system employing catalyst separation and recycle, these gummy particles cannot be handled and the operation cannot be continued. Consequently, the apparatus becomes inoperative long before the complex reaction has proceeded far enough to produce a complex liquid capable of maintaining the aluminum chloride particles tov properly dispersed in a fluid and pumpable condition.

In accordance With the'present invention, a large body oithe complex liquid is preformed and introduced into the alkylation system. The relatively smaller amount of added active aluminum chloride is maintained properly dispersed in this complex liquid without difculty, even in quiescent parts of the system. The dispersed aluminum chloride reacts slowly to form additional complex liquid without passing through.

any noticeable sticlryl or yummy stage and Without agglomeration. Moreover, in this case, the complex reaction serves to form more liquid of the same general character' as the preformed body or complex liquid used as the suspending or dispersing medium. Consequently, the character of this medium is not objectionably altered during continued operation; and the activity of the catalyst is maintained merely by adding fresh aluminum chloride to make up for that consumed. Thus, the viscosity and pumpability o the activated complex catalyst are maintained reasonably constant over lone 'periods of continuous operation, and the above-noted diculties are ets.

" ectively overcome.

the aluminum chloride in solici particle iorm,`

rather than forming a complex liquid. Consequently, all `the above-noted objections and difficulties still apply to the pretreated aluminum chloride particles, and the advantages of the` present invention are not obtained.

The following examples are given as illustratory of the present invention, but it is to be understood that the invention is not restricted thereto:

EXAMPLE l1 A refined kerosene, mainly paramnic and naphthenio in character obtained from a-mixed base crude, and having a boiling range of about 350- `515" F., was used for preparing the complex liqlll uid. kOne gallonof the kerosene was heated to 22B-240 F. in a flask equipped with a stirring device. Powdered aluminum chloride was intro duced into the flask in small increments while the heating and stirring was continued, until a total of 200 grams of aluminum chloride had been added over a period of about eight hours.

The complex was then a mobile liquid at room i temperature. The supernatant unre'ected kerosene, which separated as an upper layer after the stirring was discontinued, was removed; and the complex then allowed to stand for a further period of time in order to settle out any unreacted aluminum chloride or solid sludge. The complex liquid was then decanted and thus removed from the non-liquid sludge.

An aluminum chloridedrerosene complex liquid prepared as described above was analyzed for heat of hydrolysis by mixing with water in a calorimeter, and also for carbon plus hydrogen content expressed as the "bound hydrocarbon content. The said complex liquid was found to have a heat of hydrolysis of 314. calories per gram of complex'liquid, which calculated to 72 large calories per gram atom of active aluminum. The said complex was also found to have a carbon plus hydrogen content of 42.2% by weight on the basis of the complex liquid.

Two hundred and sixty eight grams of the above-described aluminum chloride -lzercsene complex liquid were then mixed with 25 grams of fresh powdered' aluminum chloride and 288 grams of an activated complex catalyst were obtained. This amount oi the activated complex catalyst was added to a batch reactor equipped with a stirrer together with 1.000 cc. or 560 grams of isobutane. Then 90 grams of ethylene were charged into the reactor over a period of minutes while the contents were agitated rand maintained at a temperature of 110 F. The reaction mixture was settled. the complex catalyst removed, the hydrocarbon liquid stabilized and the alkylate distilledto separate the same into a Sil-140g F. fraction and a residue boiling above 140 F. An activated aluminum chloride-kerosene complex prepared as described above was also analyzed for heat of hydrolysis and bound hydrocarbon content. The following table shows the conditions and results of this batch run:

Table 1` 268 grams of aluminum chloridekerosene complex liquid plus grams aluminum chloride Catalyst Heat of hydrolysis of activated catalyst:

Calories per gram of complex 327 Large calories per gram atom of active aluminum 68.5

Bound hydrocarbon content of activated Example II The following continuous runs were made lin a rotary 'reactor of the type shown in Fig. 2, in order to compare ,the effectiveness oi the kerosene complex liquid alone with the activated kerosene complex catalyst. in each of these runs, the reactor was charged with the catalyst and then rllled with isobutane. A hydrocarbon mix consisting of isobutane and 10% ethylene by weight was then introduced at a rate of 0.1 pound per minute at a reactor temperature of about 1lli F. Five 8-pound alkylate samples were collected from each run over a. period oi 6% hours. These alirylate samples were stabilized and distilled, and the results averaged for each run. The following table summarized the conditions and results of these comparative runs:

Fabre 2 Activcdcomplcx, C giggle? 600 cc. aluminum Catalyst muminum chlocmddkemsne ride-kerosene ggpx complex ilquid A101 Hest oi hydrolysis oi catalyst: Calories per gram oi complex 314 351 Large calories per gram atom of active umlnum 72.0 71.6 Bound hydrocarbon content of catalyst, Wt. per cent:

Determined 42.2 3&.7 Calculated 33.5 Isobutane-ethylene mol ratio 4.34 4.34 Reactor temperature. F. lll) 110 Total number of periods.- 5 5 Time in minutesnfor each eriod 30 80 C arge rate in pounds] hour 6 6 Contact time in minutes-. 11.6 10.6 Tottxl debutanized ellryl- Total volume in gel DS 0.7 1.7 Average weight per cent yield basis oleiin 96 237 311" F. fraction: Average volume per cent of alkylnte-; 0.6 97.7 Total distillate to 400 F.:

Average volume per cont of ollxylate 97.6 99.2 Bromine number of composite 0 0 O. F. octane num r o composite 92.9 92.3

The above results show that the kerosene comm plex liquid alone is comparatively inactive, producing a rvery low yield of allsylate over the rela=I tively short period of 6% hours. Moreover, the yields even in the first periods of the run with this complex liquid alone were quite low, being less than half the yields with the activated cornplex catalyst under the same conditions.

Example HI In this experiment an aluminum chloride-hydrocarbon complex liquid was prepared by reacting aluminum chloride with tertiary butyl chloride at room temperature, using one part by weight of aluminum chloride to 2.5 parts of the alkyl chloride. The reaction resulted in the breakdown of tertiary butyl chloride, with the evolution of HC1 and hydrocarbon gases, and a lowering in temperature of the reaction mixture.

The reaction mixture was allowed to stand until the evolution of gases had ceased when the reaction mixture had been brought back to room temperature. The resulting complex liquid was then separated from any supernatant hydrocar= prepared as describedl above was activated by thev addition of 200 grams of aluminum chloride. An activated catalyst prepared in this manner was tested and found to have a heat of hydrolysis of 343 calories per gram of complex, which calculated to '76.5 large calories per gram atom oi active aluminum, and a bound hydrocarbon content which analyzed 34.5% by weight, and which calculated to 32.2% based on the bound hydrocarbon content of the tertiary butyl chloride complexilquid alone plus the known amount of activating aluminum chloride added. The said activated catalyst was charged to the reactor, and the l'atter then filled with isobutane.

A hydrocarbon mixture consisting of 90% iso l butano, 9.1% ethylene, and 0.9% propyiene by weight was charged continuously to the reaction vessel and subjected to intimate contact with the catalyst, the reaction temperature being maintained et about 110 F. The hydrocarbon feed was-charged to the vessel at the rate of about one gallon oi hydrocarbon per hour per pound of activated catalyst. Charging at this rate was continued for a period ot about 26 hours. at the end ci which time the catalyst `was substantially completely spent.

.es a result of this operation, there was proa duced a quantity of allwlated hydrocarbons which amounted to ofi gallons oi totai debutari 'iced allsyiate. l pounds oi olen had been charged beiore the. above-described decrease in catalytic activity occurred.. The resulting debu tahiaed allrylate amounted to about 226% byV weicht on the basis ot the olen charged, and

about eii% by volume ci this allrylate distilled beu -levv lil li. This tir li. end point gasoline had n 4Q'. l?. lili. octane number of si@ and a hroniine number ci' il.

The above results show that the activated cata lyst.. containing s, substantial erheess ci added aluminum chloride over that required to saturate the comples: liquid, maintained its activity over u fair period ot time. in catalyst depletion runs ci this character 'with ethylene alone as the ole :linie constituent, it was found that the activated complex catalyst tended to become considerably more viscous as its activity was reduced. lin the present run, the presence of the propylene retarded the rate ci' viscosity increase of the cat alyst, and showed a pronounced eii'ect in maintaining the desired luidity thereof. As pointed out above, the combination oi the small amount or propyliene in the charge with preferably/.a small amount of HC1, together with the reculer or continuous addition of fresh aluminum chlo- 4ride to the catalyst as the operation proceeds.

` tained .over very substantial periods of continu-y ons operation. l

Exams! IV Y The following continuous runs were made to show the effect of fortiilcation of the activated complex catalyst by the addition of fresh aluminum chloride for continuation of the alkylation reaction; and they alsoillustrate the critical nature of the temperature in this isobutaneethylene alkylation reaction.

A rotary reactor of the type illustrated in Fig. 2 was charged with 600 cc. of the tertiary butyl chloride complex liquid prepared as described in Example III, .together with 200 grams of aluminum chloride to activate the catalyst. The reactor was then lled with isobutane. A hydrocarbon charge consisting of isobutane. 9.1% ethylene, and 0.9% propylene by weight was added continuously at a, rate of 6 pounds per hour. while the reactor was maintained at a temperature of '7B-85 F; 5.6 gallons of total debutanized alkylate were obtained in this Run l over a period oi approximately 26 hours, at the end of which time the catalyst was substantiallyl spent.

600 cc. of the spent complex from the abovedescribed run were then charged to a rotary -reactor together with 200 grams of fresh aluminum chloride, and isobutane to i111 the reactor. The same charge as in Run 1 above was added corrx tinuously at a temperature of 7S-85 F. over a period of about 6% hours; but the reactivated catalyst .was substantially inactive at this temperature and only about 0.6 gallon of total debutanlzed alkylate was produced for 40 pounds loi hydrocarbon charge during this portion of Run 2; The temperature of the reactor was then raised to about F., and the operation cohtinued for a 4short period oi about 2 hours. This was suilicient to determine that the activity been restored by the use'of the higher tempera-1.

ture and good yields oi alkylate were secured.

To further investigate the eiectV ci iortication, 500 cc. oi the activated catalyst from. Run 2 immediately above, together with iii@ cc. ci the spent complex from Run i above were charged to e. continuous reactor together with iiilii grams of aluminum chloride, and the reactor then iilled with isobutane. The same hydrocarbon charge was then added continuously at a reactor temperature of 110 1li. over a period ci approximately 52 hours, obtaining 12j? gallons oi total debul catalyst at a temperature of TME? it., only about 321i pounds' ci olefin could be charged before a substantial decrease in catalytic activity-oecurred, with the result that only 5.6 callous ci alltylate were obtained.. Fortiilcatiori oi' this spent catalyst from Run 1 by the addition oi aluminurn chloride tailed to restore the required activity of the catalyst for isobutane-cthylene alhylation in Run 2 at a temperature ci 'lc-t5 F., althoughthe fortified catalyst was found to be active at 110 F. In run 3 above, utilizing a fortified catalyst under the same conditions as in Run l except that a temperature of 110 F. was employed, 215.9 pounds of olefin were charged before decrease in catalytic activity occurred, and

12.7 gallons of goed quality debutanized allxylate were obtained. Moreover, the alkylate from Run 1 had a .lower percentage oi hexanes and e. high percentage of material boiling above 160 F. than the aiirylate from Run 3. The change in temperature from 'Z8-85 F. to 110 F., thus resulted. in more than doubling the life of the catalyst in enabling the catalyst to be iortied for continued alkylatlon, and in the production of a better quality alizyiate containing a higher proportion of 2,3-dlmetbylbutane.

EXAMPLE V The following runs were made to obtain a v comparison of the kerosene complex prepared as in Example i above with the tertiary butyl chloride complex prepared as in Example DI above. Each of these runs was carried out continuously in a rotary reactor of the character shown in Fig. 2 with continuous recirculation of the complex catalyst without reviviilcation or the addition of fresh aluminum chloride, in order to obtain a measure of catalyst life. The following a l u m in u m chloride compl e x 2 0 0 chloride comgrems alumiplea-+200 num chloride. grams aluminum chloride. Mol ratio lsobutanezethylene. 4.34 .34. Temperature," F 110 110. Contact timeinmins 1l 11. Volume ratio, catalyst to About 0.8:l About 0.81.

hydrocarbons in reactor. Charge rate oi hydrocarbons 6 6.

in pounds per hour. Total debutanxzed alkylate: 226 238. weight per cent yield basis of oletln. 311 F. end point fraction: 98.8 98.9 volume per cent o! alkylate.

Bromino numbcr 0. C. F. R. M. octane number... 93.8 95.0.

A. S. T. M. distillation of debutanized alkylate:

I BP. F

Volume per cent hexane fraction oi' debutanizcd alkylate.

Higher than havanes, volume per cent.

Total gallons 2,3dimothyl butano per pound oi (ree aluminum chloride.

The above results indicate excellent eectiveness for both of the activated complex catalysts,

there being a slight superiority in favor of thev tertiary butyl chloride complex catalyst.

EXAMPLE VI 6 pounds per hour. A fresh tertiary butyl chlo= ride complex liquid activated with 200 grams of aluminum chloride `eras used in each of Runs 1 and 3; the spent catalyst from Run l was fortifled with 200 gramsof aluminum chloride for Run 2; and the spent catalyst from Run 3 was icrtied with a iilre amount oi aluminum chioride for Run d. The ollowing table shows .he results of these runs:

Tobie Run 1 Run 2 Run 3 Run s Charge:

Isobutane, wt. per cent. 90. 0 99. 0 90. 0 Q9. 0

Propylene, Wt per nt 0.9 0.9 2.0 2. o

Ethylene, wt. per cent 9. i 9.1 il. 0 e. 0 Total debutenizcd alkylate, gal.. 8. 9 4. 7 4. 7 2. 3 Yield per pound active AlClc. 10. 7 3 Olen charged before decrease in catalytic activity, lb 22. 3 13. 8 1l. 5 G. 2

Composition of clkylete:

Pentanehexcne, vol. per cent. 74. 4 69. 5 67. l 64. 4

Heptane, vol. per cont 7. 3 8.8 15.8 i3.

Higher, vol. per cent 18. 3 21. 7 17. l 27. 1 311 F. fraction, vol. per cent- 97. 6 94. 8 96. 3 84. 7

r. No 0 0 0 d Octane No. C. F. R. M 93.4 93.4 92.0 92.0

- The above results showed the critical eect oi maintaining the proportion of propylene below about 10% by Weight on'the basis of the ethylene in this reaction. It Will be noted that the catalyst life in Runs 3 and 4 is only about haii that of Runs l and 2. Moreover, the quality ci the allwlate with the higher proportion of propyl-u ene of Runs 3 and 4 ls decidedly inferior to that produced in Runs 1 and 2 where the propylene was maintained within the critical range specified above.

e Examen The effect of HCl concentration in the hydrocarbon charge above the critical range specied heretofore is particularly evident in a. sharp reduction in lead susceptibility of the allryiate. Even a proportion as low as 0.13% HCl by Weight on the hydrocarbon charge gave a substantial reduction in lead susceptibility of the allrylate, as is evident from the following clear and leaded octanes obtained on typical 311 F. end point fractions of alkylates prepared from isobutaneethylene charges contag a small proportion of propylene in accordance with the present inventionL Table 5 Alkylate fraction Alfemig prepared with 0.137 by weight gfighgf of Hl in charge bon charge Clearostene No. 0.9. R. M. 90.7.

l0.5 cc. TEL/gallon" 96.8. +1.0 cc. TEL/gallon Iso-octanc+0.03 cc.

. TEL/gallon.

17 aromatic or oleiin hydrocarbon will be different from that oi.' a complex liquid prepared from a. parailln hydrocarbon or a mixed parafiinic-naphthenic hydrocarbon fraction. This is pointed out since the heat of hydrolysis of the catalyst may be utilized as a convenient control test in operation; lbut this test must be related to the particular hydrocanbon used in forming the complex liquid. Diner-ent ranges of ,heat of hydrolysis will be used in operationl for complex liquids formed from dideren't hydrocarbons, and for the activated catalysts produced therefrom. In this connection, the heat of hydrolysis expressed in calories per gram of complex catalyst is 4used for control purposes, since no effective relationship for control purposes has lbeen found between the heat of hydrolysis expressed as large calories per gram atom of active aluminumv and the alkylating activity of the catalyst. In fact, as evident from Examples l1 and III above, the calculated value oi' the heat of hydrolysis in large calories per gram atom of active aluminum for the activated catalyst tivity; but it is essential for good results in coritinuous operation, as shown by Example II above,

to add aluminum chloride to 'the complex liquid to mtain the heat of hydrolysis above 31tcalories per gram, and preferably atleast about S25-33o calories per gram. Likewise, the tertiary butyl chloride complex liquid as freshly prepared had a. heat of hydrolysis of about 324: calories per gram; and sumcient aluminum chloride should he added to this liquid to maintain the heat oi .hydrolysis of the activated catalyst above 32d calories per gram and preferably at .least about 33o-335 calories per gram. The proper control ranges of heat of hydrolysis of activated complex 18 ity of the catalyst, as best determined by analysis of the alkylate with respect to yield and quality.

While complex liquids prepared from aluminum chloride, and activated complex catalyst prepared by adding aluminum chloride to the complex liquids, have been specifically described aboverit is to be understood that other aluminum halides. such. as aluminum bromide, can be used in place of the aluminum chloride.

The expression aluminum halide-hydrocarbon complex liquid is used as a matter of convenience throughoutthe description and claims to signify the liquid produced by reaction of an aluminum halide with a. hydrocarbon or hydrocarbon fraction as wellas with an alkyl halide. The expression activated complex catalyst, or other' similar expression employing the word activated is used throughout the description and claims to catalysts formed from other hydrocarbons or poised therein in a form which resists mechanical separation, the excess aluminum chloride reed in a suspended form which was capable of heine separated from the complex liquid by eenn trifuging. The result oi this centrifuge treatment i was to reduce theheat ci hydrolysis of this ausa pended type of kerosene complex catalystfrom a value above S25-33o calories per g down to a value of about 32o calories per cram. In ce cordance with the present invention, soient aluminum chloride is initially added to the preformed complex liquid to disperse aluminum chloride in the liquid in active form. Thereafter, in continuous operation, additional aluminum chloride is added to the system to maintain hiuh activ,-

'signify the complex liquid containing added alumln'um halide in dispersed and active form.`

In my above-mentioned copending application,

vherein disclosed to produce 2,3-dimethylbutane or an alkylate consisting primarily of 2,3-dimethylbutano.

Obviously, many modiications and variations may be made in the invention as herein set forth without departing from the* spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

I claim:

1. In the continuous alkylation of isobutane with ethylene in the presence oi an aluminum chloride-hydrocarbon complex liquid catalyst, the improvement which comprises continuously introducing isobutane in liquid phase together with ciel-ins consisting of ethylene and a, controlled proportion of propylene less than about 10% by Weight of the ethylene, with the isobutane in substantial molar excess of said olens, into an alkylaticn reaction zone containing a large huid and pumpable body of the said complex liquid cou-` added dispersed active aluminum chloride, reacting iscbutune with the ethylene therein under allrylating conditions including a temperature of about lill-130 l., e, pressure cuillcient to maintain the isobutane in liquid phase,

h and 'the said controlled proportion of propylene body oi complex liquid duid and pumpable over` lons periods of continuous operation` 2. The method according to claim l. wherein a portion of the separated complexcetalyst liquid is diverted tin-ouah a catalyst activating acne where solid aluminum chloride is added hetero said portion is returned to the reaction sono..

` 19 3. In the continuous alkylation of isobutane with ethylene in the presence of an aluminumchloride-hydrocarbon complex catalyst. the improvement which comprises Ypreforxning the complex catalyst liquid by heating aluminum chloride with a material selected from the group consisting oi' kerosene and tertiary butyichloride, separating'thfresultant complex liquid from unreactedl'organic material and nonllquid sludge, adding additional aluminum chloride to the pre formedcomplex liquid in an amount sufficient to retain active dispersed aluminum chloride present in the complex liquid, Supplying e large body of the said preformed and activated' complex liquid to` an alky'lation reaction zone, continuously introducing into said zone iscbutane in liquid phase together with ethylene and a controlled proportion of prcpylene lees than about 10% by weight of the ethylene, reacting isobutane with the ethylene under alkylatina conditions including a substantial molar excess of isobutane to 20 ethylene, temperatures of about 11B-130 F., a superatmospheric pressure suiiiclent to maintain isobutane in liquid phase, and suicient propylene to maintain the fluidity of the complex catalyst liquid in continuous operation, continuously separating complex catalyst liquid from resulting hydrocarbons, returning separated complex liquid to the reaction zone to thereby maintain the liquid catalyst body within the system, and adding additional aluminum chloride to the catalyst body as the reaction proceeds to maintain active dispersed aluminum chloride present in the complex liquid in an amount in excess ot that which will react with hydrocarbons present therein to form complex liquid under the said alkylat- -ing conditions, the said additional aluminum chloride together with the propylene in the hydiocarbon charge serving to maintain the body of complex liquid fluid and pumpable over long 2@ periods of continuous operation.

LOUIS A. CLARKE. 

